In response to recent demands for energy savings in image formation, efforts are being made to reduce toner fixation temperatures. One proposal has been to reduce fixation temperatures still further by using a polyester with a low softening temperature. Because the softening temperature is low, however, the toner particles may fuse together and blocking may occur when the toner is left standing during storage or transportation.
As a means of achieving both blocking resistance and low-temperature fixability, a technique has been proposed using a crystalline resin with a sharp melt property, meaning that its viscosity decreases sharply when its melting temperature is exceeded (Patent Literatures 1 to 3).